Data processing apparatus employing permanent magnet inhibiting means



R. LUKIANOV 3,407,396 DATA PROCESSING APPARATUS EMPLOYING PERMANENT Oct. 22, 1968 MAGNET INHIBITING MEANS Filed Dec. 30, 1964 2 Sheets-Sheet 1 INVENTOR. ROMAN LUKIANOV ATTORNEY.

Oct. 22, 1968 v R, LUKIANOV 3,407,396

DATA PROCESSING APPARATUS EMPLOYING PERMANENT MAGNET INHIBITING MEANS- Filed Dec. 30, 1964 2 SheetsSheet z INVENTOR.

ROMAN LUKIANOV Af-TORNEY.

United States Patent 3,407,396 DATA PROCESSING APPARATUS EMPLOYING PERMANENT MAGNET INHIBITING MEANS Roman Lukianov, Framingham, Mass, assignor to Honeywell Inc., a corporation of Delaware Filed Dec. 30, 1964, Ser. No. 422,378 Claims. (Cl. 340-174) The present invention relates in general to new and improved data processing apparatus and in particular to an improved keyboard system for use in conjunction with magnetic logic circuitry.

An example of a magnetic core logic circuit wherein the present invention may be employed is illustrated in Patent No. 3,157,862 by Joseph J. Eachus, which is assigned to the assignee of the present invention. The circuit shown in the patent contains a plurality of bistable magnetic cores which are threaded by a common drive winding to which drive pulses are periodically applied. Each core has one or more sense windings and is further threaded by a plurality of inhibit windings which may link additional cores in accordance with the program which is to be carried out. The application of a signal of a predetermined amplitude and polarity to one of these inhibit windings will inhibit each core linked by the winding from switching stable states upon the application of a drive pulse. Thus, by selectively inhibiting certain cores, the application of a drive pulse will result in a predetermined signal code obtained as an output from the aforesaid plurality of cores.

Where keyboard encoding is employed, the inhibit signals are commonly applied by means of a key-operated switch or relay connected between a DC source and the inhibit winding. This gives rise to problems such as contact arcing, contact chatter and contact bounce. The contacts are also sensitive to dust and dirt particles and are further subject to wear. In addition, undesirable transients are produced upon switching, which may erroneously serve to inhibit the cores linked by the line in which the transient occurs.

To this end, electrical contact substitution devices have been employed in prior art keyboard systems, which operate on the principle of manipulating a magnetic circuit of which the core or cores that are to be inhibited are a part. These devices may substitute either for a multiplecontact, key-operated switch, or for a key-operated relay having a plurality of contacts. Prior art devices of this type may take the form of cores consisting, for example, of two segments which are selectively joined to form a core coupling around predetermined signal-carrying wires. The magnetic properties of such a core coupling are far from satisfactory, it being virtually impossible to provide a core having clearly definable characteristics. Any dirt or wear between the contact surfaces of the segments will make it diflicult to reproduce the exact magnetic properties of a core as the segments are opened and closed. In other prior art devices, a permanent magnet is disposed in close proximity to the cores which are to be inhibited from switching, while an interposer adapted to shunt the magnet flux, is selectively positioned between the magnets and the cores. Alternatively, permanent magnets are brought into close proximity with the cores, thereby influencing the switching characteristics of the latter. In both instances where permanent magnets are employed in prior art contact substitution devices, the flux path set up includes air gaps which invariably give rise to flux fringing. The stray magnetic fields thus created increase the possibility for error insofar as they may inhibit cores from switching. Moreover, the presence of air gaps in the flux path requires the use of a relatively powerful permanent magnet in each instance.

Where the magnetic characteristics of a plurality of ice cores are manipulated at the same time, prior art devices have proved incapable of providing a simultaneous response for all cores. Ordinarily, the response is obtained in sequence from the respective cores, governed, for example, by the linear motion of the interposer. Thus, a strobe pulse may have to be generated when the last one of the plurality of cores responds, to indicate the validity of all previous core responses. The requirement for strobing materially increases the cost and the complexity of such equipment.

It is the primary object of the present invention to provide a keyboard system wherein the foregoing disadvantages are avoided.

It is another object of the present invention to provide a simple and economical keyboard system for manipulating the magnetic characteristics of predetermined numbers of cores.

It is a further object of the present invention to provide a key-operated contact substitution system for use in conjunction with magnetic core logic circuitry, wherein the magnetic characteristics of predetermined numbers of cores are simultaneously manipulated.

These and other objects of the present invention, together with the features and advantages thereof will be-' come apparent from the following detailed specification, when read in conjunction with the accompanying drawings, in which:

FIGURE 1 illustrates a preferred embodiment of the present invention;

FIGURE 2 illustrates in enlarged detail a portion of the apparatus of FIGURE 1; and

FIGURE 3 illustrates a modification of the apparatus of FIGURE 1.

With reference now to the drawings, FIGURE 1 illustrates a key-operated contact substitution system wherein a pair of supports 10 and 12 are mounted on a common base 14. First and second non-magnetic mounting bars 16 and 18 respectively, which may consist of brass in the preferred embodiment of the invention, are positioned between the supports 10 and 12. The mounting bar 16 supports a magnetic circuit 20, while the mounting bar 18 supports a magnetic circuit 22 which is substantially identical to the circuit 20.

In the preferred embodiment illustrated in FIGURE 1, the magnetic circuit 20 contains three annular, magnetic cores 24, 26 and 28, which are supported in a common plane by core holders 30, 32, 34 and 36. The cores may consist of a ferrite material having a high retentivity and a low coercive force. As shown in FIGURE 1, successive core holders are mutually spaced along the length of the mounting bar 16 to which they are fastened. Each pair of successive core holders includes a pair of facing surfaces comprising an arcuate portion 38 intermediate a pair of flat surface portions 40 and 42 which converge toward the core. The arcuate surface portion of each core holder engages a portion of the periphery of each core which is less than half of the total periphery. The radius of the arcuate surface is the same as that of the core periphery in order to maximize the contact area therebetween. A pair of air spaces 44 and 46 is defined between each pair of successive core holders.

A pair of keeper bars 48 and 50 is mounted on the mounting bar 16 so as to contact the end core holders 30 and 36. The keeper bars terminate in a pair of mutually spaced ends 52 and 54 symmetrically positioned with respect to the cores. The ends 52 and 54 include a pair of rounded grooves 51 and 53 respectively, opening outward from the cores. In the preferred embodiment of the present invention, the keeper bars, as well as the core holders, may consist of a magnetic material, eg soft iron, having a high permeability and low retentivity.

In similar manner, the magnetic circuit 22 includes three annular, magnetic cores 56, 58 and 60, having a high retentivity and a low coercive force. The cores are held by the core holders 62, 64, 66 and 68 which are mounted in successively spaced relationship along the length of the mounting bar 18. A pair of keeper bars 70 and 72 is fastened to the mounting bar 18 in a manner to contact the end core holders 62 and 68. The lastmentioned keeper bars terminate in a pair of mutually spaced ends 74 and 76 which include a pair of grooves 73 and 75 respectively, opening outward from the cores. As in the case of the magnetic circuit 20, the core holders, as well as the keeper bars of the magnetic circuit 22, consist of a high-u, low-retentivity magnetic material.

A permanent bar magnet 78, which may consist of a material commercially available as Alnico, is shown in bridging contact with keeper bar ends 74 and 76, seated in the rounded grooves 73 and 75. This is illustrated in greater detail in FIGURE 2 which provides an exploded view of the pertinent component structure. The magnet 78 is seen to extend through a non-magnetic cross bar 82. The latter is supported between a pair of arms 84 by means of a pair of pivot pins 80 which mate with corresponding holes 81 in the crossbar. The arms 84 are fastened to a key lever 86 which is pivotably supported on the vertical support by means of a pivot 88 and which terminates in a key 90. A compression spring 94, suitably supported on an extension 96 of the vertical support 10, bears against the key lever 86 in a manner to maintain the permanent bar magnet 78 in bridging contact with the keeper bar ends 74, 76 of the magnetic circuit 22.

In the position illustrated, the permanent magnet induces a flux in the magnetic circuit 22 which is indicated by means of arrows in FIGURE 1. The flux is seen to travel through the magnetic keeper bar 72, whence it enters the core holder 68. The latter is magnetically separated from the succeeding core holder 66 by air spaces, both core holders being mounted on the nonmagnetic bar 18. Since the material of the core 60 constitutes the path of least reluctance, the flux must flow through the core, the direction of flux flow being the same in both core halves. This is similarly the case in the cores 58 and 56 which, together with the core 60, are thus inhibited from switching. The flux path is completed through the end core holder 62 and the keeper bar 70 which is in contact with the opposite pole of the bar magnet 78.

In FIGURE 1, all core windings have been omitted for the sake of clarity, the invention being applicable to different kinds of magnetic core logic circuitry. It will be clear, however, that the biasing of the cores 56, 58 and 60, in the position of the permanent bar magnet 78 shown in FIGURE 1, will prevent these cores from switching. Conversely, the magnetic circuit remains unbiased while the bar magnet is in the position shown so that the cores 24, 26 and 28 are free to be selected for switching in the logic circuit of which they form a part. The application of drive pulses to these cores, if they are not otherwise inhibited, will then cause them to switch to provide a predetermined output code on the sense windings linking these cores.

When the key 90 is depressed, the bar magnet 78 moves up into bridging contact with the ends 52 and 54 of the keeper bars 48 and to seat in the grooves 51 and 53. The cores 24, 26 and 28 are now inhibited, while the cores 56, 58 and of the magnetic circuit 22 become free to switch. The application of drive pulses to the latter cores will then result in output pulses in the sense windings of these cores, provided the cores are not otherwise inhibited. In this manner, the assertion and the negation of a particular digital code may be simultaneously provided, so that complementary core logic may be carried out.

'It will be noted that the flux path is simultaneously established or broken for all three cores of a given magnetic circuit. The resultant simultaneous response of all the cores in the circuit thus permits the magnetic logic circuitry of which the cores are a part, to accept the code output from the core sense windings without the necessity of strobing. In addition, the symmetrical disposition of the cores relative to the permanent magnet assures a substantially uniform flux density in each core, so that all cores are inhibited or de-inhibited to the same extent. This property of the present invention is further aided by the presence of a continuous, low-reluctance flux path which reduces flux fringing.

Ideally the bar magnet must be capable of pivoting about its own axis, as well as about the axis defined by the pivot pins 80, to assure a proper mechanical contact and the absence of air gaps. In the present invention, this requirement is obviated by the presence of the rounded grooves in the ends of the keeper bars. The grooves serve to engage the bar magnet regardless of its orientation about its own axis. As a consequence, cross-talk between magnetic circuits operated by different keys is prevented. Furthermore, the efiiciency of each magnetic circuit is increased so that a relatively weak permanent magnet may be used to inhibit a larger number of cores than would otherwise be possible. The increased efliciency of the magnetic circuit is due, in part, to the close physical contact between the bar magnet and the ends of the keeper bars.

FIGURE 3 illustrates a modification of the apparatus of FIGURE 1 wherein applicable reference numerals have been retained. The magnetic circuit 20 which is shown in FIGURE 1 is replaced in this embodiment of the invention by a keeper bar 97 which, like the keeper bars 70, 72 and the core holders 62, 64, 66 an '68, consists of a magnetic material having a high permeability and a low retentivity. The keeper bar 97 is fastened to the non-magnetic mounting bar 16 and includes a pair of mutually spaced ends 98 and 99 having rounded grooves .93 and respectively, adapted to seat the permanent bar magnet 78. The magnet is adapted to make bridging contact with the ends of the keeper bar 97 when the key is depressed. Thus, the embodiment of the invention shown in FIGURE 3 provides a magnetic circuit 22, the cores of which are normally inhibited. The cores are capable of providin an output code on their linking sense windings when the key is depressed. The mag netic circuit defined by the keeper bar 97 is closed when the bar magnet 78 contacts the ends 98 and 99, so-that flux fringing is minimized in this position.

FIGURE 2 provides an indication of the overall thickness of each keyboard unit. This is primarily determined by the thickness of the cores which is relatively small. As a consequence, the present invention readily lends itself to keyboard use, since largenumbers ofmagnetic circuits may be mounted in a relatively limited space, side by side on the common supports 10 and 12. In such an arrangement, the flux linkage between adjacent magnetic circuits, as well as the physical dimensions of the linking wires, establish the parameters with respect to the spacing of successive magnetic circuits.

The present invention provides a simple and economical structure for generating selected digital codes in response to keyboard actuation, such structure being readily adaptable for use in magnetic core logic circuitry. The invention is not confined to the illustrated preferred embodimcnt. For example, the mounting bar need not be brass, but may consist of any nonmagnetic material. Similarly, the number of cores shown is exemplary only.

The keeper bars may be integral with the end core holders. The bar magnet may have a square or a rectangular cross section adapted to make surface contact only with the keeper bars. The spring 94 may be positioned on the other side of the support 10 and be used in tension. Thus, it will be apparent that numerous modifications, substitutions and equivalents will now occur to those skilled in the art, all of which fall within the true spirit and scope contemplated by the present invention.

What is claimed is:

1. In a keyboard unit, a first magnetic circuit comprising a plurality of core holders positioned in a common plane and spaced along the length of a non-magnetic mounting bar, said core holders consisting of a highpermeability material having low retentivity, a magnetic core positioned between the facing surfaces of each pair of successive core holders and having high retentivity and a low coercive force, each of said facing surfaces including a pair of flat surface portions converging in the direction of said core and an arcuate surface portion intermediate said converging portions, said arcuate surface portions having a radius substantially identical to that of the periphery of said core and contacting a portion of the latter, said magnetic circuit terminating in a first pair of mutually spaced ends, a second magnetic circuit terminating in a second pair of mutually spaced ends, a permanent bar magnet, and a key-operated mechanism adapted to move said bar magnet into bridging contact with a selected one of said pairs of spaced ends, said magnet being adapted to inhibit said cores from switching.

2. The apparatus of claim 1 wherein at least said first magnetic circuit includes a pair of keeper bars consisting of a material having a high permeability and low retentivity and terminating in said first pair of ends, said keeper bars being positioned on said mounting bar in said common plane and contacting the core holders at opposite ends of said plurality of core holders.

3. The apparatus of claim 2 wherein each of said ends is grooved to accept said magnet so as to make close physical contact therewith.

4. The apparatus of claim 1 wherein said key-operated mechanism includes means for pivotably supporting said magnet about an axis substantially normal to the direction of magnet motion between said first and second pairs of ends.

5. In a keyboard-operated encoder, a first magnetic circuit comprising a plurality of successively spaced core holders positioned in a common plane and consisting of a high-permeability material having low retentivity, each pair of successive core holders including facing arcuate surface portions, a magnetic core positioned in said common plane between each pair of successive core holders and having high retentivity and a low coercive force, said arcuate surface portions each engaging a portion of the periphery of said core, shunt means extending from opposite ends of said plurality of core holders and having substantially similar magnetic properties as the latter, said shunt means terminating in a first pair of mutually spaced ends symmetrically positioned with respect to said cores, a second magnet circuit terminating in a second pair of spaced ends, and a permanent magnet movably adapted upon actuation from said keyboard to bridge a selected one of said pairs of ends, said magnet being adapted to inhibit each core from changing its magnetic state.

6. In an encoder employing magnetic core logic, a magnetic circuit comprising a plurality of core holders successively spaced in a common plane and consisting of a high-permeability material having low retentivity, an annular, high-retentivity magnetic core positioned between each pair of said core holders and forming a part of said logic circuit, the facing surfaces of said pair of core holders each having an arcuate surface portion intermediate a pair of flat surface portions, each arcuate surface portion contacting less than one half of the periphery of said core, said magnetic circuit terminating in a pair of mutually spaced ends, a permanent magnet adapted to bridge said ends, and means for moving said magnet into contact with said ends, said magnet being adapted to saturate said cores to inhibit the latter from changing their magnetic state.

7. The apparatus of claim 6 and further including a continuous keeper b-ar presenting another pair of spaced ends to said magnet, said magnet being selectively adapted to make bridging contact with one of said respective pairs of ends.

8. The apparatus of claim 6 and including a further magnetic circuit substantially identical to said first recited circuit and positioned in mirror image relationship with respect to the latter in said common plane, said permanent magnet being disposed between said circuits and being selectively adapted to bridge a chosen pair of said ends, the cores of said magnetic circuits being adapted to provide complementary codes.

9. In a manually operable keyboard encoder, a succession. of keyboard units positioned in spaced parallel planes, each of said units including a pair of mutually spaced mounting bars carrying a pair of substantially identical magnetic circuits symmetrically positioned between said bars in the plane thereof, each magnetic circuit comprising a plurality of core holders fastened to said mounting bar and successively spaced along the latter, an annular magnetic core having a high retentivity and a low coercive force positioned between the facing surfaces of each pair of successive core holders, each of said surfaces including a central, arcuate surface portion adapted to contact a portion of the periphery of said core and a pair of flat surface portions sloping away from said core on both sides of said arcuate portion, a pair of keeper bars positioned in said plane and fastened to said mounting bar so as to contact the end core holders, said keeper bars terminating in a pair of mutually spaced ends each including a rounded groove facing the other magnetic circuit in said plane, said keeper bars and said core holders consisting of a high-permeability, magnetic material having low retentivity, a permanent bar magnet of circular cross section positioned between said magnetic circuits in each plane and being symmetrically disposed with respect to the cores of each of said circuits, said magnet being adapted to bridge a pair of said ends by seating in the grooves thereof, and a key-operated mechanism corresponding to each of said planes for laterally transposing said magnet to complete a selected one of said pair of symmetrically positioned magnetic circuits in said plane, said permaanent magnet being adapted to saturate the selected magnetic circuit to prevent the cores the-rein from switching, the cores in each pair of said symmetrically positioned magnetic circuits being adapted to provide the assertion and the negation of a digital signal.

10. The apparatus of claim 9 wherein said key-operated mechanism includes a pivoted arm normally biased to a first position, means at one end of said arm for depressing the latter to move it selectively to a second position, and means at the other end of said arm for pivotably supporting said permanent =bar magnet substantially at its center.

References Cited UNITED STATES PATENTS 3,042,866 7/ 1962 Kadlec 307-88 X 3,140,403 7/1964 Morwalp 307-88 3,197,747 7/1965 Kramer 340-174 3,263,221 7/1966 Van Der Hock 340-174 X BERNARD KONICK, Primary Examiner.

J. F. BREIMAYER, Assistant Examiner. 

9. IN A MANUALLY OPERABLE KEYBOARD ENCORDER, A SUCCESSION OF KEYBOARD UNITS POSITIONED IN SPACED PARALLEL PLANES, EACH OF SAID UNITS INCLUDING A PAIR OF MUTUALLY SPACED MOUNTING BARS CARRYING A PAIR OF SUBSTANTIALLY IDENTICAL MAGNETIC CIRCUITS SYMMETRICALLY POSITIONED BETWEEN SAID BARS IN THE PLACE THEREOF, EACH MAGNETIC CIRCUIT COMPRISING A PLURALITY OF CORE HOLDERS FASTENED TO SAID MOUNTING BAR AND SUCCESSIVELY SPACED ALONG THE LATTER, AN ANNULAR MAGNETIC CORE HAVING A HIGH RETENTIVITY AND A LOW COERCIVE FORCE POSITIONED BETWEEN THE FACING SURFACES OF EACH PAIR OF SUCCESSIVE CORE HOLDERS, EACH OF SAID SURFACES INCLUDING A CENTRAL, ARCUATE SURFACE PORTION ADAPTED TO CONTACT A PORTION OF THE PERIPHERY OF SAID CORE AND A PAIR OF FLAT SURFACE PORTIONS SLOPING AWAY FROM SAID CORE ON BOTH SIDES OF SAID ARCUATE PORTION, A PAIR OF KEEPER BARS POSITIONED IN SAID PLANE AND FASTENED TO SAID MOUNTING BAR SO AS TO CONTACT THE END CORE HOLDERS, SAID KEEPER BARS TERMINATING IN A PAIR OF MUTUALLY SPACED ENDS EACH INCLUDING A ROUNDED GROOVE FACING THE OTHER MAGNETIC CIRCUIT IN SAID PLANE, SAID KEEPER BARS AND SAID CORE HOLDERS CONSISTING OF A HIGH-PERMEABILITY, MAGNETIC MATERIAL HAVING LOW RETENTIVITY, A PERMANENT BAR MAGNETIC OF CIRCULAR CROSS SECTION POSITIONED BETWEEN SAID MAGNETIC CIRCUITS IN EACH PLANE AND BEING SYMMETRICALLY DISPOSED WITH RESPECT TO THE CORES OF EACH OF SAID CIRCUITS, SAID MAGNET BEING ADAPTED TO BRIDGE A PAIR OF SAID ENDS BY SEATING IN THE GROOVES THEREOF, AND A KEY-OPERATED MECHANISM CORRESPONDING TO EACH OF SAID PLANES FOR LATERALLY TRANSPOSING SAID MAGNET TO COMPLETE A SELECTED ONE OF SAID PAIR OF SYMMETRICALLY POSITIONED MAGNETIC CIRCUITS IN SAID PLANE, SAID PERMANENT MAGNETIC BEING ADAPTED TO SATURATE THE SELECTED MAGNETIC CIRCUIT TO PREVENT THE CORES THEREIN FROM SWITCHING, THE CORES IN EACH PAIR OF SAID SYMMETRICALLY POSITIONED MAGNETIC CIRCUITS BEING ADAPTED TO PROVIDE THE ASSERTION AND THE NEGATION OF A DIGITAL SIGNAL. 